show_font_picker runs `wezterm ls-fonts --list-system` via
wezterm.run_child_process, parses out unique font family names, and
presents them through the existing fuzzy InputSelector so English/
Korean font menu entries no longer require typing an exact,
correctly-spelled font name. A "직접 입력..." choice at the top falls
back to the previous free-text prompt_font flow, also used
automatically if the font list can't be retrieved.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>